A month of battery life? im going to call ********... unless you dont ever use your phone i put mine on a stable governor brightness always down and NFC/Data/Bluetooth/WiFi off and i come home with 50% gone

Lipo batteries deteriorate with time (and temperature)
A lipo can lose as much as 40% capacity per year if it is kept quite warm (100% charge)
Mine is new, high capacity, my CPU is triggered by demand, few background programs running, backlight is only on for 10s after use, etc.
I generally use it to play music when I drive but when I was on vacation I was getting 700-750 hours on a charge.